The Science of Roller Coasters

It doesn't matter if you’re a seasoned veteran or climbing in for the first time, roller coasters are a staple of summer. From your county fair to Coney Island, these amusement park rides have spent their life capturing the imagination of children across the globe. Whether it was the dread of having to wait another year before you were tall enough to ride or the nervous excitement of waiting for your chance to scream through each freefall, it’s safe to say that you probably have great memories of times spent strapped to a roller coaster.

That’s because, every year, more than 300 million people ride roller coasters at U.S. amusement parks alone. A number totaling more than the population of the United States, this figure doesn’t include all the coasters or riders across the globe, but it does showcase just how popular roller coasters are — people just can’t get enough of a safe thrill ride!

So, why do people love roller coasters so much? Well, to answer that, we need to look at the history of roller coasters.

The Growth of Thrill Rides

Today’s roller coasters can trace their family trees back to 16th century Russia, where wood-framed ice slides sent riders down 70-foot slopes. Later, these same mountains became summer attractions with the introduction of wheeled carts and wooden ramps. 

In the United States, LaMarcus A. Thompson’s famous Coney Island roller coaster is widely considered the first successful commercial coaster. Known as the Gravity Switchback Railway, Thompson’s roller coaster debuted in 1884, becoming an instant success and a fixture of New York. Bringing long lines of eager riders and thrill seekers, the coaster brought in an average of $600 a day, nearly $17,000 by today’s measures.

While the famous Coney Island coaster is considered the first commercially successful ride, the first patents for similar gravity-centered rides were issued as early as 1872, 12 years before Thompson’s success.

Since their wooden, ski-slope roots, modern roller coasters have come a long way. The title of The World’s Largest Steel Coaster belongs to Kingda Ka, a 456 ft tall roller coaster at the Six Flags Great Adventure park in New Jersey.

At Ferrari World in Abu Dhabi, the steel roller coaster Formula Rossa takes adventure seekers on the fastest coaster ride possible, reaching speeds of up to 149 miles per hour.

If you’re looking for the longest ride, head to Nagashima Spa Land in Japan, where the Steel Dragon 2000 takes you on an 8,133 ft long ride.

Thrilling Me with Science

Since the first time you sat in a roller coaster, you’ve been participating in a ton of hands-on science — primarily, by offering yourself up to the will of gravity.

As we know, most roller coaster cars don’t rely on motors. Just like their Russian ancestors, roller coasters rely on gravity and a high starting point. Using tracks and motors (similar to an escalator), all coaster rides start out the same way, with an initial ascent. By climbing to the highest point on the ride, the roller coaster is not only building anticipation in every rider, but it is also charging up with a bank of potential energy./p>

Potential energy, expressed in science as U, is energy that is stored within an object, not in motion but capable of becoming active. When at rest, every object has rest mass potential energy; if the object is in a position to be affected by gravity and to fall, it has gravitational potential energy. Once an object is in motion, potential energy is converted to kinetic energy, which is the energy of motion. - Margaret Rouse

Once a roller coaster crests it’s initial ascension, the potential energy it’s been storing gets, with the help of gravity, released as kinetic energy. As gravity applies constant downward force, the coaster’s tracks guide the car’s path by channeling the force of gravity. As the track slopes upwards, the car decelerates as the downward force of gravity pulls on the car, and likewise, as the track slope down, the car accelerates as the force of gravity pushes down. 

As Tom Harris and Cherise Threewitt summarize,

Since an object in motion tends to stay in motion (Newton's first law of motion), the coaster car will maintain a forward velocity even when it is moving up the track, opposite the force of gravity. When the coaster ascends one of the smaller hills that follows the initial lift hill, its kinetic energy changes back to potential energy. In this way, the course of the track is constantly converting energy from kinetic to potential and back again.

This fluctuation in acceleration is what makes roller coasters so much fun. In most roller coasters, the hills decrease in height as the train moves along the track. This is necessary because the total energy reservoir built up in the lift hill is gradually lost to friction between the train and the track, as well as between the train and the air. When the train coasts to the end of the track, the energy reservoir is almost completely empty. At this point, the train either comes to a stop or is sent up the lift hill for another ride.

A Simple Reminder

At a basic level, roller coasters are only machines that use gravity and inertia to send carts along a set path. The idea behind them is really no more complicated than a set of train track toys or 16th-century Russian sleds. When you sit in a roller coaster, all you’re doing is riding down a hill.

So why are they so much fun? Why do hundreds of thousands of people strap into a roller coaster every year?

Because roller coasters allow us to experience science in ways we usually can’t.

Whether it’s the thrill of weightlessness or the tingling memory of your first ride, roller coasters remind every rider of the power of gravity, the adrenaline rush of inertia and the excitement of potential energy.

If you’d like a more in-depth look at the science behind roller coasters or if you want to bring physics and engineering lessons like this into your classroom, check out the Discover Engineering learning solution from PCS Edventures:

The Discover Engineering Kit developed by PCS Edventures is designed to cultivate the young engineers of tomorrow. In order to prepare students for rapidly evolving technology, this kit combines the latest methods proven by research to get students excited about learning. While introducing the basic concepts of engineering, activities in the Discover Engineering Kit foster confidence, critical thinking and other important 21st-century skills.